It took police three months to relent and release the information, but since then, exposing the use of government cars for private business has become Ou's new "job".

After making breakfast for his family, Ou goes for a walk near his house in Haizhu district or takes a bus to Yuexiu district, where the offices for complaints of the Guangzhou Bureau of Public Security and the Guangzhou Price Bureau are located.

Ou knows the importance of evidence and having a witness, so the minute he started having a conversation with the driver in front of the temple fair, he pressed the "record" button on his cell phone.

"It's outdated but has all the functions I need, taking photos, recording and uploading the photos to my Sina Weibo," said Ou.

During Spring Festival this year, he posted a picture of an invoice on his micro blog to accuse a civil servant's wife of buying meals at public expense. He was also one of the first residents who entered a public hearing for the adjustment of water prices last February.

"Rather than spending the rest of my life at ease, I prefer making full use of my time to do something I believe benefits society," said Ou.

"My wife tried to persuade me to stop meddling and enjoy the idle life of chatting over tea with friends and going for a walk in parks. But I just can't keep silent when I witness wrongdoing," said Ou.

Last September Ou filed a lawsuit against three local government departments that he blamed for allowing a construction site to intrude for too long into a public park.

"Some people dislike Ou's outrageous expressions of dissatisfaction, but they can't deny the existence of the problems Ou takes aim at," said Chen Xiaozhao, who was Ou's lawyer for the case.

Lu Qing, an officer from Guangzhou Office of Housing Security, described Ou as reasonable.

Lu dealt with Ou's complaint about the lack of gas pipes in the houses of some people living with disabilities in 2010. He recalled that Ou at first was hampered by his little knowledge of government procedures to deal with complaints. But later Ou helped calm residents by explaining the procedures he learned from Lu.

Now, to raise well-founded complaints, Ou has been studying laws.

"Only with supervision from people like Ou can the government keep improving its work," said Lu.